By Izzy Ross
Laurie Stanek shovels hay in front of a group of young, black and white Holstein cows.
“We’re out here at 5 o’clock every morning to get started feeding the babies,” she said. In a nearby barn, she points to a small calf shakily getting to its feet.
“That guy over there was yesterday’s new one,” she said. “They’re born about 100 pounds, 120 pounds.”
Stanek has worked at her family’s dairy farm in Antrim County for almost 50 years. Right now, they have about 200 milking cows.
This is among the Michigan farms that have to abide by new state and federal measures to protect their animals against the bird flu.
Officially called H5N1, this latest outbreak of the virus emerged in wild birds in Europe in 2020. In 2022, it was detected in commercial flocks in the United States. It’s led to the deaths of tens of millions of farmed birds and infected many mammals, from sea lions to foxes.
The jump to cows is new.
The first reported case from cattle was in Texas earlier this year. And Michigan has reported the most cases of the bird flu in dairy herds in the country — officials here say that’s because of widespread testing. It also has two of the nation’s three confirmed cases of the disease in people (the other was a dairy worker in Texas).
Scientists say controlling the disease is important, because this latest jump to cattle could pose an increased threat to human health, as well as to other animals.
So far, nine states have confirmed the presence of bird flu in dairy herds, according to the U.S. Department of Agriculture.
Across the country, the response has been rocky. Some states have pushed back against federal efforts to address the virus. Public health experts have warned that the true reach is likely greater that official counts, and have raised concerns about the lack of testing. The federal government announced that it would spend $824 million on its response, and the USDA just launched a voluntary pilot program to test cow milk in bulk.
An ‘extraordinary emergency’
Last month, Michigan declared an “extraordinary emergency.” Officials said the flu is a threat to animal health, human health, trade and the economy. The state’s largest egg producer laid off 400 workers last month amid the outbreak. In cows, bird flu causes a reduction in milk production. It may also be passed from dairy facilities to poultry farms, where it could be deadly.
“We want to make sure that we’re limiting the further spread of the virus, so that we’re continuing to protect human health, and we don’t have so much virus in the environment that could potentially mutate and affect humans in a different way,” said Tim Boring, the director of the state Department of Agriculture and Rural Development.
The Centers for Disease Control and Prevention have maintained that the danger to the public is relatively low. But farm workers face increased risk of exposure to the bird flu; the CDC has said it’s likely that those who have tested positive contracted the virus from cows. The people who experienced the illness recently have reported mild symptoms.
Over the past month, farms have faced new state and federal biosecurity requirements. The USDA has required that lactating cows moving across state lines receive a negative test.
And Michigan has prohibited poultry or lactating cows from being shown at events like fairs, and says farms should limit the people and animals coming in.
That aspect isn’t a huge concern for the Stanek farm, which has what’s called a “closed herd.”
“We raise our own, so they don’t come up against other herds that have been in other states or other places. So they’ve all been raised here,” Stanek said.
To lower the risk of infection, the state says farms should also name a biosecurity manager. The Staneks appointed one of their adult sons to that post, where he’s responsible for designating a secure perimeter around the herd and keeping track of visitors.
How the illness moves
The question of how the virus has jumped from birds to cows is, so far, unanswered. And scientists say gaining a better understanding of how the bird flu moves between animals is critical to determining how to respond to this outbreak and plan for the next one.
“I’m a virologist by training, and my other virologist buddies and I all have to admit: None of us saw this coming,” said Kim Dodd, the director of the Veterinary Diagnostic Laboratory at Michigan State University.
“We didn’t expect to find [highly pathogenic] avian influenza in dairy cattle, and to find that it amplifies so well, and that we have so much virus in the milk,” she said. “And so that’s really a big part of trying to understand, you know, what do we do about that to be able to help control the outbreak.”
When poultry are exposed to or contract the bird flu, they usually either die from the disease or are euthanized, which generally stops the viral spread. That’s not the case for cows.
“These guys recover after a period of seven to 10 days of mild to moderate illness,” Dodd said. “So those animals are still there and still producing virus while they recover, which gives individuals who are caring for them the opportunity to come into contact with that virus and potentially spread it themselves.”
The climate factor
Looming in the background is climate change. Its role in this outbreak of H5N1 is unclear. But generally, research has shown that climate change could join a host of other factors in making the transmission of viruses between species more likely — something called “viral spillover.”
“Absolutely, as we see climates change, we see changes in migratory patterns and the timing of migratory patterns,” Dodd said. “To what degree climate change may have played a role in how long this outbreak has gone on, I think, remains to be seen.”
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